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Data di pubblicazione: 2016
Da: ConchBooks, Harxheim, Germania
The land snail Cernuella virgata (da Costa, 1778) is widely considered as a pest to be quarantined in most countries. In this study, the complete mitochondrial genome of C. virgata is published. The mitochondrial genome has a length of 14,147 bp a DNA base composition of 29.07% A, 36.88% T, 15.59% C and 18.46% G, encoding 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes and two ribosomal RNA (rRNA) genes. The complete nucleotide composition was biased toward adenine and thymine, A+T accounting for 69.80%. Nine PCGs and 14 tRNA genes are encoded on the J strand, and the other four PCGs and eight tRNA genes are encoded on the N strand. The genome also includes 16 intergenic spacers. All PCGs start strictly with ATN, and have conventional stop codons (TAA and TAG). All tRNAs fold into the classic cloverleaf structure, except tRNAArg, tRNASer(UCN), tRNASer(AGN) and tRNAPro. The first three lack the dihydrouridine arm while the last lacks the T?C arm. There are 502 bp long noncoding regions and 418bp long gene overlaps in the whole mitochondrial genome, accounting for 3.54% and 2.95% of the total length respectively. Phylogenetic analyses based on the sequences of the protein coding genes revealed a sister group relationship between the Hygromiidae and the Helicidae. 15 pp., 4 figs, gr. 8.
Data di pubblicazione: 2016
Da: ConchBooks, Harxheim, Germania
The sinistral Camaena species are mainly distributed in southern China and northern Vietnam. There is a total of eight species or subspecies of sinistral Camaena recorded at present. By systematically collecting specimens in Guangdong, Guangxi and Yunnan in southern China and the northern areas in Vietnam, two new species, Camaena lingyunensis Zhou & Lin, sp. n. and Camaena detianensis Zhou & Lin, sp. n. have been discovered. These new species are here characterised based on the comparison of shells, their reproductive system, the molecular phylogenetic analyses of the mitochondrial genes COI and 16S, and the nuclear gene ITS2. Detailed descriptions of the morphological characters, the DNA sequences, and the habitat of the two new species are given. Differential comparisons with related species are provided as well as a key to the sinistral species of Camaena. New taxa: Camaena detianensis n. sp., Camaena lingyunensis n. sp. 17 pp., 5 figs, gr. 8.